Search

Modern systems, civilian (e.g. automotive), and military (manned and unmanned aircraft, surface vehicles, submerged vessels), suffer initial design faults or failure modes (FMs), including software bugs, which detrimentally affect the system's reliability and availability. FMs must be removed or mitigated in impact during initial testing, including accelerated testing, in order for the system to meet its reliability requirements and operate satisfactorily in the field. This paper concerns models for reliability growth in which the behaviors of FMs are assumed independent, but of different types. Test effort is guided by prior information, expressed probabilistically, on the random number and tenacities of such FMs that are of various origins in the designs. Estimation of the numbers of FMs that will ultimately activate while in the field is considered here. [ABSTRACT FROM AUTHOR]

Abstract: Integrity of the long arm of the X chromosome is important for maintaining female fertility and several critical regions for normal ovarian function have been proposed. In order to understand further the importance of specific areas of the X chromosome, we describe a series of 20 previously unreported patients missing part of Xq in whom detailed phenotypic information has been gathered as well as precise chromosome mapping using array Comparative Genomic Hybridization. Features often associated with Turner syndrome were not common in our study and excluding puberty, menarche and menstruation, the phenotypes observed were present in only a minority of women and were not specific to the X chromosome. The most frequently occurring phenotypic features in our patients were abnormalities of menstruation and fertility. Larger terminal deletions were associated with a higher incidence of primary ovarian failure, occurring at a younger age; however patients with similar or even identical deletions had discordant menstrual phenotypes, making accurate genetic counselling difficult. Nevertheless, large deletions are likely to be associated with complete skewing of X inactivation so that the resulting phenotypes are relatively benign given the amount of genetic material missing, even in cases with unbalanced X;autosome translocations. Some degree of ovarian dysfunction is highly likely, especially for terminal deletions extending proximal to Xq27. In conjunction with patient data from the literature, our study suggests that loss of Xq26–Xq28 has the most significant effect on ovarian function. [Copyright &y& Elsevier]

Summary: Background: Turner syndrome, one of the most common cytogenetic abnormalities, is characterised by complete or partial X-chromosome monosomy. Cancer risks in women with Turner syndrome have not been clearly established. We aimed to compare the risk of cancer in women with this syndrome with that of the general population. Methods: We formed a national cohort of 3425 women who were cytogenetically diagnosed with Turner syndrome in Great Britain between 1959 and 2002. Identifying information for these patients was sent to the National Health Service Central Register (NHSCR) for England and Wales and to the NHSCR for Scotland. Individuals who were identified on this register were followed-up for cancer incidence. Standardised incidence ratios (SIRs) and 95% CIs were calculated on the basis of the number of cancers observed compared with that expected based on national incidence rates. Cumulative risk estimates were obtained by use of the Kaplan-Meier method. Findings: A total of 58 299 person-years were accrued during the study, with a mean of 17·0 years (SD 8·6) follow-up per patient. 73 malignancies other than non-melanoma skin cancer occurred (SIR 0·9 [95% CI 0·7–1·2]). Risks were significantly increased for tumours of the CNS (n=13; 4·3 [2·3–7·4]), especially for meningioma (n=7; 12·0 [4·8–24·8]) and childhood brain tumours (n=3; 10·3 [2·1–30·1]), and for cancers of the bladder and urethra (n=5; 4·0 [1·3–9·2]) and eye (n=2; 10·5 [1·3–37·9]), compared with the general population. However, the risk of breast cancer was significantly decreased (n=10; 0·3 [0·2–0·6]). The SIR for cutaneous melanoma was 2·2 (95% CI 1·0–4·4; n=8), and one of the ocular cancers was a melanoma. The risk of corpus uteri cancer was significantly increased at ages 15–44 years (n=3; 8·0 [1·6–23·2]). During follow-up, five women, all with a Y-chromosome lineage, developed gonadoblastoma of the ovary, corresponding to a cumulative risk of 7·9% (95% CI 3·1–19·0) by age 25 years in this group. Interpretation: This study shows that, in addition to having an increased risk of gonadoblastoma, women with Turner syndrome seem to be at increased risk for meningioma and childhood brain tumours, and possibly bladder cancer, melanoma, and corpus uteri cancer, but are at a decreased risk for breast cancer. Reasons for these risks might relate to genetic and hormonal factors or to the effects of hormonal treatments given to women with Turner syndrome. [Copyright &y& Elsevier]